宽带小型化限幅放大器设计

Design of broadband compact limiting amplifiers

摘要:

基于共集共基电路的宽带小型化限幅放大器设计，利用三极管发射结特有的IV特性，将输入三极管工作在共集组态，并在后级级联共基组态三极管，实现输入信号非饱和削波，达到限幅目的。由于共集与共基放大电路都具有宽带特性，故其级联后电路特性也具有宽带特性。本文利用该结构设计了一款宽带限幅放大器，工作带宽覆盖10~200 MHz，增益大于25 dB，限幅输出功率2 dBm，输入输出回波损耗均大于20 dB。利用薄膜电路工艺设计实现小型化限幅放大器设计，电路尺寸为7.15 mm×8.1 mm，与印制板(PCB)电路相比，尺寸明显较小。该电路结构精简，性能优越，适合分离元件电路设计。

Abstract:

Common collector common base cascaded transistor structure can compose limiting amplifiers because of special IV curve between the emitter junctions. The first transistor is common collector and the second transistor is common base so that the amplifier can limit the output wave to non-saturation, which means limiting the output power. Because both of the common collector and common base transistors have broadband structures, the final amplifiers are of broadband characteristic. A broadband limiting amplifier is designed, which operates from 10 MHz to 200 MHz, with the gain of 25 dB, the limiting power of 2 dBm, the return loss upper 20 dB. A compact limiting amplifier is designed by thin film circuit technology, whose size is 7.15 mm×8.1 mm, smaller than that by traditional Printed Circuit Board (PCB) technology. The limiting amplifier has smaller size and more excellent performance.